Stages of Growth: Month by Month

Month 1

As the fertilized egg grows, a water-tight sac forms around it, gradually filling with fluid. This is called the amniotic sac, and it helps cushion the growing embryo.

The placenta also develops. The placenta is a round, flat organ that transfers nutrients from the mother to the baby, and transfers wastes from the baby.

A primitive face will take form with large dark circles for eyes. The mouth, lower jaw, and throat are developing. Blood cells are taking shape, and circulation will begin. The tiny "heart" tube will beat 65 times a minute by the end of the fourth week. By the end of the first month, your baby is about 1/4 inch long – smaller than a grain of rice!

Month 2

Your baby's facial features continue to develop. Each ear begins as a little fold of skin at the side of the head. Tiny buds that eventually grow into arms and legs are forming. Fingers, toes and eyes are also forming.

The neural tube (brain, spinal cord and other neural tissue of the central nervous system) is well formed. The digestive tract and sensory organs begin to develop. Bone starts to replace cartilage.

The head is large in proportion to the rest of the baby's body.

By the end of the second month, your baby is about 1 inch long and weighs about 1/30 of an ounce.

At about 6 weeks, your baby's heart beat can usually be detected.

After the 8th week, your baby is called a fetus instead of an embryo.

Month 3

Your baby's